Setsuna is a perverted instructor who is unable to invoke magic. As a part-time Instructor at the Royal Academy of Magic, he continually tells his students to self-study. The new students who entered the academy with high expectations are disappointed in Setsuna, and judging him to be incompetent, they challenge him to a Geas duel.

《Will you resign if I win?》
《"I"? Surely you mean "we"... All of you have been pretty annoying, so I want you all to take me on. But in return, you know what will happen if you lose, right?》

Setsuna plays with the special students, who are the best in a hundred years, with perverse and astonishing magic that is unthinkable in common sense! But behind the demon-like behavior, could there be a true purpose...?